Add font support to PageSerializer

Source/core/css/CSSFontFaceRule.h

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * (C) 2002-2003 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2002, 2006, 2008, 2012 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 24 matching lines @@
     static PassRefPtr<CSSFontFaceRule> create(StyleRuleFontFace* rule, CSSStyleSheet* sheet) { return adoptRef(new CSSFontFaceRule(rule, sheet)); }
 
     virtual ~CSSFontFaceRule();
 
     virtual CSSRule::Type type() const OVERRIDE { return FONT_FACE_RULE; }
     virtual String cssText() const OVERRIDE;
     virtual void reattach(StyleRuleBase*) OVERRIDE;
 
     CSSStyleDeclaration* style() const;
 
+    StyleRuleFontFace* styleRule() const { return m_fontFaceRule.get(); }
+
 private:
     CSSFontFaceRule(StyleRuleFontFace*, CSSStyleSheet* parent);
 
     RefPtr<StyleRuleFontFace> m_fontFaceRule;
     mutable RefPtr<StyleRuleCSSStyleDeclaration> m_propertiesCSSOMWrapper;
 };
 
+inline CSSFontFaceRule* toCSSFontFaceRule(CSSRule* rule)
+{
+    ASSERT_WITH_SECURITY_IMPLICATION(rule->type() == CSSRule::FONT_FACE_RULE);
+    return static_cast<CSSFontFaceRule*>(rule);
+}
+
 } // namespace WebCore
 
 #endif // CSSFontFaceRule_h